A Three-Dimensional Model Coupled Mechanical Consolidation and Contaminant Transport

Abstract

Contaminant transport is a common process for a waste disposal site, which is a practical concern in geo-environmental field. It is essential to study the contaminant transport behavior in impermeable clay liner. Considering the anisotropy of a clay barrier in permeability, a three-dimensional model coupled mechanical consolidation and contaminant transport is developed for simulation of contaminant transport through a deforming porous medium. This is based on the combination of Biot's theory and the theory of contaminant transport. Meanwhile, porosity is viewed as a coupling parameter. The influence of soil consolidation deformation and permeability anisotropy on contaminant transport can thus be determined reasonably. Transport equations are solved by using the finite-element software COMSOL Multiphysics. A parametric study has moreover been conducted to understand the influence of contaminant source types and adsorption modes, including constant contaminated source, attenuation contaminated source, linear adsorption, Freundlich adsorption, Langmuir adsorption. The simulation results indicate that the permeability anisotropy has a negligible effect on contaminant transport, adsorption modes have a significant impact on transport depth and range, and the concentration distribution of contaminant with different contaminated source types have showed a marked difference.

Archives of Environmental Protection

“…Pollution transport in any type of ground is a complex issue due to the need of taking into account many physical and climatic factors in a given climatic zone in which this transport takes place (Chiang 2005, Taniguchi andHolman 2010). To describe this transport mathematical models have been successfully used for many years (Chalfen 2012, Chiang 2005, Kolditz et al 2016, Morway et al 2013, Szymański and Janowska 2016, Zhang and Fang 2016, Zheng and Wang 1996. For such models, tools for assessing groundwater quality without the need for expensive fi eld research ("in situ") are convenient.…”

“…For such models, tools for assessing groundwater quality without the need for expensive fi eld research ("in situ") are convenient. As a rule, in pollution transport mathematical models the most important physicochemical and biochemical processes occurring in the ground are described, such as: advection, dispersion, adsorption, biological or chemical reactions (biodegradation/denitrifi cation) or the process of radioactive decay (Chalfen 2012, Chiang 2005, Kolditz et al 2016, Morway et al 2013, Szymański and Janowska 2016, Zhang and Fang 2016, Zheng and Wang 1996. It can also be said that mathematical description of all these processes is very diffi cult due to the lack of accurate methods of measuring the ongoing metabolism of these processes in the ground (Fang et al 2012).…”

“…This remark refers in particular to complex biochemical processes occurring in the ground (Fang et al 2012, Morway et al 2013, Zheng and Wang 1996. It can be observed that the greatest reduction in pollutants' concentration in groundwater is caused by the adsorption process (treated as a variable in time, ground adsorption capacity) (Chalfen 2012, Chiang 2005, Kolditz et al 2016, Morway et al 2013, Szymański and Janowska 2016, Zhang and Fang 2016, Zheng and Wang 1996.…”

“…The study of literature shows that time-dependent adsorption capacity of the ground is widely analyzed in relation to various types of grounds as well as various contaminants (Chalfen 2012, Chiang 2005, Morway et al 2013, Szymański and Janowska 2016, Zhang and Fang 2016, Zheng and Wang 1996. It can be noticed that in the case of a long period of time in which a pollutant fl ows in aquifer the ground adsorption capacity can gradually become depleted.…”

“…The adsorption isotherm models are described mathematically by means of linear or nonlinear isotherms (Kowal et al 1990, Seidel-Morgenstern 2004. Parameters of adsorption models depend on type of pollutants fl owing in groundwater, physical features of ground as well as climatic conditions constituting climatic zone (Kowal et al 1990, Seidel-Morgenstern 2004, Szymański and Janowska 2016, Zhang and Fang 2016, Zheng and Wang 1996.…”